I have only walked out of two films in my lifetime: The Lion King live action remake, and Oppenheimer.
Watching a film in a theater should be an enjoyable, effortless experience. The audience should be given a concise, cohesive plot to follow through to a satisfying conclusion. Much to my disappointment, watching Oppenheimer was mentally taxing to the point of fatigue and exhaustion.
That mental exhaustion didn't arise from any profound, poignant commentary on Robert Oppenheimer's life, his choices, or even the specter of nuclear holocaust, but rather the mismanagement of the technical aspects of the film's direction, pacing, and writing. What should be a well-orchestrated symphony of connected plot points in an already well-understood story is instead a frenetic, haphazard collage of scenes unceremoniously clothespinned and hot glued together with jump cuts. Those jump cuts seem to come before the current scene reaches any natural stopping point, creating a feeling of endless whiplash.
It is truly baffling to me that such a manic, disorganized film could ever materialize from such a well-documented, widely-understood biography about a real person, particularly one that has been covered multiple times in previous films throughout cinematic history. This wasn't a mistake. It wasn't an oversight or lapse in judgement. That such a renowned and accomplished director would take a story that has already been written by history, chop it up, and make a plot salad that rivals the worst specimens of amateur fiction took effort; willful, deliberate, intense effort.
That's perhaps the worst part about the film: It makes efforts to present itself as cerebral, eclectic, and "too smart for the viewer to understand." This arrogance in writing is on perpetual display as characters frequently break from expected behavior to provide expositional dialogue that doesn't fit the context of what is happening. During one sex scene Robert's partner abruptly dismounts for no stated reason, walks up to his bookcase, opens a random book to a random page, and forces him to read the Sanskrit text to her as she mounts him again and resumes awkwardly rocking back and forth on his pelvis like he's the world's most lethargic mechanical bull. This wasn't artsy or interesting. It added nothing to the plot, yet I couldn't escape the feeling that Nolan truly thought this was an important moment in the film, and that anyone who "didn't get it" was too stupid to realize what just happened.
Oppenheimer is a pretentious, condescending, schizophrenic misadventure in artful cinema. I could not possibly recommend it any less. What I do recommend is watching some of the older films that deal with this subject matter. They are better than Oppenheimer in every conceivable way.